Thermostatic control device



THERMOSTATIC CONTROL DEVICE Filed June 28, 1949 IIIIIHA WL" g i 538 MI5 IN VEN TOR.

HwrzyxEverhard ATTRNEYS Patented Mar. 4, 1952 UNITED STATES PATENT OFFICE THEBMOSTAIIC CONTROL DEVICE Harry H. Everhard, Canton, Ohio Application June 2,8, 1949, Serial No. 101,820

2 Claims. (01,236-33) The invention relates generally to thermostatic controls for automatically regulating burners heating fluid tanks or reservoirs, and more particularly to thermostatic control devices for hot water heaters, and especially adapted for domestic hot water heaters including the type shown in my prior Patent No. 2098g489, issued November 9, 1937.

Certain prior thermostatic control devices for this purpose are complicated and relatively expensive, and are designed especially to be used with only one particular type of automatic heater. Moreover, these prior devices include as a thermostatic element an expansible tube which projects radially into the Vhot `water tank through a" tapped pole normally provided in standard cylindrical hot water boilers. The expansible tube cannot be inserted diametrically into such a standard boiler until the vertical filler pipe lo-V cated in the center of the boiler is removed and bent or offset to pass around the thermostatic tube. This operation involves additional trouble and expense in the installation of the thermo, static control device.

With these prior devices, the expansible tube is usually copper because of the necessity to minimize corrosion, but copper has a relatively small coefcientof expansion, so that a limited amount of linear expansion of the tube is ob tained with which` toregulatethe operation of the fuel valve which supplies the burners. Asa result, the control of the burner is difficult to. maintain accurately Within the critical temperature range and the fuel valve must be designed so as to have a relatively large eifective area for transmitting vsufficient fuel with a very small opening move.- ment of the valve.

Accordingly, such prior thermostatic controls require relatively large parts, someV of which are usually castings, and the control devices are consequently relatively large and heavy, and` expensive `to manufacture.

It. is an object of the present invention to provide a novel thermostatic control device which is extremely smalland compact in construction, and inexpensive to manufacture and install.

Another object is to provide av novel thermostatic control device -which is adapted to be used with various types and sizes of hot water tanks and heaters.

Another object is to provide a novel thermostatic control device which is mounted entirely on the outside ofthe heater tank, making it easy to install.

Another object is to'provide a novel :thermo- 2 A.static cori-.trol device hav-iris an elonsatedlbia'ae tubeiooated adiacenti@ .tneeiiteriorof tnewater tank. for obtaining sreaterwexpaneibility- A further object to-nrovide novel lever for multiplying the eiieet ofy the expaneible ele-- another object is `to Provide novel thermo# static control device Whichgives greater accuracy o f control within the Leftieal temperaturevange: e still iurther object-is to provide andrei 'thermostatie Control.V devioewhieh utilizes relativelt7 `Small fuel valve .andre1atedf-lealta-` Finailv, it is an obieotof the presentinvention to provide a simple, Compact and inexpensive thermostatic control device in Which partslare Substantially all `made from fStandard tube and bar Stock, without .requiring any castings.

These and other objects are .accomplished by the parte. elements, arrangements and e.oniloina.-

tions comprising. the `praterit invention. a pree `ferieol embodimentof which is-illuetratedbv way of example in the accompanying drawing as exempliiying the beet known modeof oarryingeut, the inventiony :said `piet-erred. .embodilnont,` beine described in. detail infthefollowing specification, and the scope of the invention beine. defined' in the appended claims.

in aeneralftermsthe invention may loe eet iortii as-.ineluding a Se1i=oontained thermoetatie .ce .trol device poeitioned within a .enamel-Shaped. housingl adapted to be moantedaionesiiiaa water tank, there beine an elongated exnansibletbrass tube in the ,housing insulated .thereirom and heat-conducting relation to the tank.` with a .oa bon rodfslidable in thetube and operating a th' olf class `lever fillerameri` inatubular valve housing. secured to one end of theexpansible tane, said lever being arranged to aetuate anv axial'pinfor opening and closing a elaine ,Dressed fuel val-ve in said fuel valve. housing,` and a tubular fuel supply housing connected to Said: fuel valve houti-ng andnavine apilot lsupply passageway leading tiaerefrroin and. atreeulating: ,vaivezn said passa-ee Way.

`Referring tothe drawing in whicha preferred embodiment of the invention is y,shown `by way of example:

Figure V1 is averticalsectional view.` with parts broken away, of the novel thermostatic control; device ,applied to 4the Side of a hot water tank- Fig. 2 is a similar fragmentary view onl a lie-.- duced Sea-1e.. .Showing the manneivoi neigt-.iria` the expaneiblefthermoetatic :tube in neat=eoiid1ietins relation` to -theetank :vs/all;

Eie- 3 is a `planfsentieriai .view as on .lineal-3,

a,5ss,224

Fig. 1, showing the manner of mounting the thermos tatie control device on a tank wall in conJ unction with a not water heater applied to the side o1 tile Water tank;

rig. l 1s a transverse sectional view as on line 4-4, Fig. 1;

Fig. a 1s a transverse sectional view as on line 5-5, Fig. 1;

rig. o is a fragmentary cross sectional view as on line u--6, Fig. 1;

nig. I is a fragmentary cross sectional View as on line `|-`I, Fig. l; and

Fig. c 1s an enlarged fragmentary sectional View as on line 8 8, Fig. 1.

Similar numerals refer to similar parts throughout the several views of the drawing.

An ordinary cylindrical hot water tank or boiler is maicated fragmentarily at IU, and the novel thermostatic control device comprising the present invention is shown in a vertically disposed position alongside the exterior of the cylindrical tank wall. As indicated in Fig. 3, the invention is snown in connection with a hot water heater attached to the side of the tank for heating the tank wall, such as shown in my Patent No. 2,098,489. However, it will be understood that the invention may be utilized in connection with other types of hot water heaters.

In the embodiment shown, the thermostatic control device is mounted within a channelshaped housing indicated generally at II, having two parallel legs I2 extending substantially radially outward from the tank wall I and connected at their outer ends by a web I3. At suitable locations, slots I4 are provided in one corner of the channel II, and holes I5 are formed in the opposite leg I2 so that clamping bolts I6 can extend across the channel member I I. The clamping bolts I6 are each connected as by welding to a strap I'I which encircles the tank I0 and is connected to a similar bolt I6 and channel II on the opposite side of the tank.

Between these two opposite channels H is mounted the insulated sheet metal shell or jacket indicated generally at I8 within which is located the combustion chamber of the heater, and the jacket I8 is provided with notched brackets I9. Bolts 20 having wing nuts 2l are used to connect the brackets I9 to the channels II, as indicated in Fig. 3, so that the shell I8 of the heater is tightly clamped against the side wall of the tank. 1 In this embodiment, one of the channels II serves as the housing for the self-contained thermostatic control device comprising therpresent invention, but it is obvious that in applying the invention to other types of heaters, the shape and dimensions of the housing may be modified. Referring to Fig. '1, the bottom section of the control device is indicated generally at 22 and may be described as a tubular housing for the fuel supply chamber 23. Preferably the housing 22 is made from a piece of standard brass bar stock, and is provided at itsupper end with a threaded portion 24 for attachment to the adjoining section of the' device. A main supply valve`25 is screwed into the side of the chamber 23 for supplying fuel such as natural or artificial gas to the chamber, and a gas supply line 26 is screwed into the outer end of the valve.

Preferably the inner end of the Valve is provided with an internal annular shoulder 21, and a strainer screen 28 is seated at one end within the shoulder 21. The other end of the screen is seated within a cap I29 which abuts the inner wall of the chamber "Z3-and preferably the screen 4 is crimped radially inwardly into a polygonal shape, as shown in Fig. 8, to increase its eiiective area. A spring clip 3J is attached at one end to the cap 29 and engages in the bore of the valve 25, for mounting and maintaining the shape of the screen 28 as it is forced into position.

A pilot valve supply duct 3l is drilled longitudinally into the housing 22 from the bottom end into the inner end of the chamber 23, and the bottom end of the duct is plugged as indicated at 32. A screw threaded needle valve 33 is threaded transversely through the housing member 22 and its inner end seats on one end of a port 34 communicating with the duct 3l. An axial pilot valve passageway 35 drilled from the bottom of housing member 22 connects with the port 34, so that when the needle valve 33 is opened, gas will flow around the cap 29 into duct 3|, and from the duct 3| into the passageway 35 and thence into the pipe 36 which supplies gas to the pilot burner.' 'A lock nut 33a is provided on the needle valve 33 to hold it in adjusted position.

The threaded upper end 24 of the housing 22 is provided with a bore 38 communicating with the fuel supply chamber 23 and preferably having a tapered outlet portion 39 at its upper end. The threaded portion 24 is screwed into the internally threaded lower end 40 of a tubular housing section indicated generally at 4I which contains the fuel supply regulating valve 42. The housing section 4I is preferably made from standard brass bar stock. The regulating valve 42 is positioned in a bore 43 for seating against the shoulder 44 at the top of the bore, and a spiral spring 45 having its upper end axially engaged with the valve 42 normally holds the valve in closed position. The bottom of the spring is preferably seated in an annular cup 46 which abuts the upper end of the housing 22.

Preferably the outer periphery of the valve 42 is provided with slotted portions 41 for allowing passage of the gas around the valve 42 and valve seat 44 when the valve is opened, and thence into the reduced bore 48 which communicates with a clover-leaf bore 48a (Fig. 6) extending into a transverse bore 49 in which is screwed the angular outlet fitting 50, and the main burner supply pipe 5I is connected with the tting 5B and preferably extends downwardly along the exterior of the channel housing Il. The burner pipe 5I and the pilot burner pipe 36 are preferably made of brass tubing which is easily bent to suitably connect the pipes to their respective burners.

The upper end of the housing member 4I is provided with a vertical threaded bore 52 which communicates with the inner end ofthe transverse bore 49, and is thus laterally offset from the pin 59. An elongated expansible brass tube 53 is screwed into the vertical bore 52 and extends upwardly adjacent to the tank wall into the upper portion of the channel il. A non-expansible carbon rod 54 is slidably mounted within the tube 53, and preferably has a rounded metallic contact button 55 at its upper end and a similar button 56 at its lower end, which may be tapered as shown. Preferably the button 59 engages the intermediate portion of'a lever 51 which is fulcrumed at one end 58 in the bore 49, and its other end engages an axial pin 59 extending through the bore 48rd and abutting the valve 42 at its lower end. The cloverleaf bore 48a provides a series of gas passageways around the pinv and ribs between the passageways for guiding the pin. Thus relative movement of the carbon rod 54 with respect to the brass tube 53 and housing `cap member 64screwed Aon the tube.

linelnber 4l will force the valve .42 downwardly `against :the spring 45 `to open the valve .and a1,- `low gas to flow through bores 4.8. and `48.01I into bore 4 9.

The lever 51 is preferably made inexpensively from 4a sheet. metal fstamping and has flanges at its side edges to strengthen the same. The fulcrum end 58 of thelever is preferably curved upwardly and inserted through a slot in a cup member 6|]l which is secured in the inner end of the transverse bore 49 with a press fit. The other end of the lever 51 is embossed upwardly at 6I where it abuts the pin 59. Thus, the surfaces of the lever which engage the cup 60, the contact button 56J and the pin 59 are all in the same plane.

The upper end ofthe carbon rod 54 is `adjustably engaged by a pin 63 which extends above the upper end of the brass tube 53 and into a adjusting the pin 63 longitudinally of the tube preferably includes a screw 65 which is screwed into the top of the cap 64 and abuts the upper end of the pin63. A pointer or indicator 66 is secured to the head 61 secured on the screw and extends laterally through a slot 68 in the leg I3 of the channel I I. A bracket member 69 is preferably secured to the web I3 of the housing channel by a screw 10, and one end of the bracket is engaged around the cap 64 to support the same, while the other end 1I extends angularly outwardly through the slot 68 and is provided with a scale for cooperating with the pointer 66 in adjusting the thermostatic control device to change its critical temperature.

Packing means is provided around the pin 63 to prevent leakage of gas which passes from the transverse bore 49 upwardly through the brass tube 53. This packing means preferably includes graphite packing 12 which is compressed between two bushings 13 and 14 within the upper end of the tube when the cap 64 is screwed thereon.

vThe means for conducting heat from the tank wall I to the expansible tube 53, preferably comprises a strip 15 which preferably is formed of thin sheet brass and has a winged U-shape in cross section. The closed portion 16 of the U fits closely around the expansible tube 53, as best shown in Fig. 4, and the wing portions 11 are adapted to abut the tank wall when the closed U portion is engaged around the tube 53. Preferably a curved strip of spring steel 18 is interposed between the closed portion 1B of the strip and the web I3 of the channel housing for urging the conductor strip 15 toward the tank, the lower end of the spring 18 being secured to the web I3 and the upper end engaging the closed portion 16 of strip 15, as best shown in Fig. 2.

Thus the wings 11 are held in abutment with the tank wall II) while the inner edges of hous ing channel legs I2 may be spaced slightly away from the tank, as in Fig. 4. Preferably suitable heat insulating material 80 is inserted within the channel housing II and around the conductor strip 15 to insulate the channel housing from the tank and strip 15 while the heat from the tank is being conducted by the conductor strip to the expansible tube 53.k

The length of the expansible brass tube 53 is calibrated so that when the tank wall Ill is heated by the water therein to a temperature of approximately 150 F., the expansion of the tube relative to the non-expansible carbon rod will have the effect of raising the button 56 and allow the pin 59 to move upwardly which permits the spiral `spring 45 to close the valve 42. thus closing olf Means for zthesupplyoigas through the tube 5I to theniai'r burner. When the temperature `of the water `drops slightly.. lthe contraction of the tube 5.3 wille-euse the lower end 4,of the carbon rodiil t0 press ,downwardlyon the lever 51 to force the pin `59 .downwardly land open the valve 42 against vSince the tube 54 is madeof brass, which has a `relatively high coefficient ,of expansion, and the ,small diameter, `because the `amount of its opening movement is such as to pass a relatively large amount of, gas through the valve when it is open.

If the expansible tube 53 and carbon rod 54. are calibrated to operate the valve 42 to maintain the vternperature of the water in `the tank at F., the indicator 66 is attached to the head 61 so as to be positioned at the center of the scale on bracket 1I when that temperature is being maintained. If it is desired to adjust the control device for operating the valve at a slightly higher or lower temperature, the indicator is moved toward the H or C end of the scale respectively. Moving the indicator toward the H end will turn the screw 65 downwardly to force the adjusting pin 63 against the carbon rod 54 to extend its effective length slightly, thus requiring a slightly greater amount of expansion of tube 53 and a correspondingly slightly higher temperature of the Water in the tank to close the valve 42.

The novel thermostatic c-ontrol device is compact and inexpensive in construction, and is easy to install on the exterior of various types and sizes of hot Water tanks and heaters because it does not require insertion of a thermostatic element into the tank. Moreover, since the expansible element is a brass tube located along the exterior of the tank, greater expansibility and greater accuracy of control within the critical temperature range is obtained. The device can be made large of brass bar stock and utilizes a small control valve to control a substantial volume of fuel.

In the foregoing description, certain terms have been used for brevity, clearness and understanding, but no unnecessary limitations are to be implied therefrom beyond the requirements of the prior art, because such words are used for descriptive purposes herein and are int-ended to be broadly construed.

Moreover, the embodiment of the improved construction illustrated and described herein is by way of example, and the scope of the present invention is not limited to the exact details of construction.

Having now described the invention, the construction, the operation and use vof a preferred embodiment thereof, and the advantageous new and useful results obtained thereby; the new and useful constructions, and reasonable mechanical equivalents thereof' obvious to those skilled in the art, are set forth in the appended claims.

I claim:

1. A thermostatic control device for a tank heater, including a channel housing, means for securing said channel housing against the exterior of the heater tank with the open side of the channel adjacent the tank wall, an expansible brass tube within said channel housing, the lower 'end of said tube being connected to a fuel valve housing within said channel housing, a U-shaped conductor strip fitting around said expansible tube and abutting said tank wall, spring means between said channel housing and conductor strip for holding said strip in abutment with said tank wall, a spring pressed control valve in said fuel valve housing, and a non-expansible rod slidable in said expansibletube and operatively connected to said control valve.

2. A thermostatic control device for a tank heater, including a channel housing, means for securing said channel housing against the exterior of the heater tank with the open side of the channel adjacent the tank wall, an expansible brass tube within said channel housing, the lower end of said tube being connected to a fuel Valve housing within said channel housing, a U-shaped conductor strip tting around said expansible tube and abutting said tank wall, spring means between said channel housing and conductor strip for holding said strip in abutment with said tank Wall, va spring pressed .control REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 308,955 Eastman Dec. 9, 1884 986,760 Robertshaw Mar. 14, 1911 1,732,565 McCaw Oct. 22, 1929 1,794,531 Newell Mar. 3, 1931 2,044,397 Persons June 16, 1936 2,057,496 Lumsden Oct. 13, 1936 2,115,431 Shively Apr. 26, 1938 2,157,296 Mantz May 9, 1939 

